The present invention relates to communications systems and, more particularly, to a communication system used in a data processing system between a base station and a plurality of remote data terminal devices.
In data processing systems which include either a host processor and a plurality of remote data terminal devices or a master and a plurality of slave terminal devices, communication is accomplished in many systems using RF radio communications in which information is transmitted over predefined radio frequency channels. The major types of transmission systems are either phase shift systems in which wide band modulation is obtained at a given frequency, or else a rapid or frequency-hopping system in which information is transmitted for a short period on a carrier of given frequency, and is then transmitted on a carrier of different frequency chosen according to a predetermined code. Frequency hopping systems incur overhead requiring the transmitted sequence on each frame of data to hop into a channel regardless of the presence of an interfering signal or the occurrence of multipath fading in that channel, thus increasing the bit error rate.